Pharmaceutical compositions containing N-palmitoylethanolamide and use thereof in the veterinary field

ABSTRACT

The present invention relates to a method for treating eosinophilic granuloma in a Feline comprising administering a pharmaceutical composition, the composition comprising N-palmitoylethanolamide. The present invention also relates to said pharmaceutical composition and the process for the preparation thereof.

This is a 371 of PCT/IT99/00259 filed Aug. 6, 1999.

The present invention relates to pharmaceutical compositions containingN-palmitoylethanolamide (palmidrol) for use in the veterinary field,particularly for the treatment of the eosinophilic skin condition infelines which is normally known as Eosinophilic Granuloma Complex, andof tendonous keloids in horses.

The eosinophilic condition in felines (Moriello K et al, 1997, Handbookof Small Animal Dermatology, pp. 205-208, Pergamon Press) has clinicalsigns such as erythema, pruritis and alopecia, and skin symptoms whichare recognizable in the form of eosinophilic plaque (EP), eosinophilicgranuloma (EG), and miliary or papulo-scabby dermatitis, which canappear in the animal individually or simultaneously or at differenttimes.

EP is a circumscribed area of erosion and exudation associated withclinical signs such as erythema, pruritis and auto-induced alopecia.Although they may appear anywhere on the skin surface, the lesions arelocated preferentially in the inguinal or perianal regions or in themedial region of the upper rear leg. The characteristic hystopathologyof EP shows considerable cell infiltration in the perivascular spaces,associated with epidermal hyperplasia, spongiosis and ulceration.

EG appears as an erythematous, alopecic and raised area generallylocated on the caudal face of the rear paws on the extremities (the clawbed and the pads), in the oral cavity, or on the chin. Thecharacteristic hystopathology of EG appears as a diffuse granulomatousdermatitis associated with areas of collagenolysis.

Miliary dermatitis is similar to EP but less extensive and with theformation of scabs.

Regardless of whether it is in the form of EP or EG, eosinophilicgranuloma with lesions, is a highly recurrent condition. For thisreason, animals suffering from eosinophilic granuloma, in the formeither of EP or of EG, are subject throughout their lives, tointermittent or continuous treatments with antihistamines andcorticosteroids the side effects of which, particularly in treatment oflong duration, are known and documented.

The identification of active ingredients which can alleviate or resolvethe inflammatory picture, at the same time ensuring maximum tolerabilityand an absence of adverse reactions, is an objective of considerableinterest in veterinary treatment.

Tendonous keloids represent one of the most common chronicmanifestations of tendinitis which arise in horses—and in particular incompetition horses—as a result of acute inflammations of the tendons, aswell as partial or complete traumatic lesions and also lesionsassociated with haemorrhage and oedema.

Tendonous keloids appear as soft, easily palpable masses of variablesizes and are constituted by fibrous tissue with thickenings andadhesions in the peritendonous area. Horses with chronic tendon symptomsof this type notice pain with clear lameness which greatly comprisetheir competitive performance.

The treatment of these symptoms, when they are chronic, is particularlycomplex since the anti-inflammatory drugs normally used (FANS andcorticosteroids) are more effective in the acute phases than in theconsequent chronic manifestations.

Up to now, various treatments have been tried with little success; inparticular, it has been noted that the intratendonous administration ofcorticosteroids is contraindicated. Up to now, use has been made of veryquestionable operations such as superficial burning, percutaneoussplitting of the tendons, or implantation of carbon fibres.

Basically, up to the present time, there has been no pharmacologicaltreatment which has solved the chronic symptomatic manifestations oftendinitis in horses.

It has now surprisingly been found that N-palmitoylethanolamide (commoninternational name palmidrol) is effective in the treatment ofeosinophilic granuloma in cats, for both EP and EG lesions, and oftendonous keloids in horses. In the latter case in particular, acomplete recovery of the animal with the possibility of a return to thecompetition circuit has been confirmed.

The subject of the present invention is therefore the use ofn-palmitoylethanolamide, preferably in micronized and/or co-micronizedform, for the preparation of pharmaceutical compositions for veterinaryuse, particularly for the treatment of eosinophilic granuloma in cats,for both EP and EG lesions, and of tendonous keloids in horses.

A further subject of the present invention is pharmaceuticalcompositions containing N-palmitoylethanolamide in micronized and/orco-micronized form.

The treatment of cats with N-palmitoylethanolamide provides for theadministration of the drug in quantities of from 1 to 50 mg/kg/die for aperiod of between 15 and 60 days. A preferred treatment scheme providesfor a daily administration of 10 mg/kg of body weight for 30 consecutivedays.

The treatment of horses with N-palmitoylethanolamide provides for theadministration of the drug in quantities of from 0.5 to 5 g/die,preferably 2 g/die for a period of between 20 and 150 consecutive days,preferably between 30 and 120 days.

The following examples explain the invention and the preferred method ofimplementing it without, however, being limiting thereof.

BIOLOGICAL EXAMPLES Example A Effect of Oral Treatment withN-palmicoylethanolamide in Eosinophilic Skin Condition in Cats

Method

Included in the investigation were 15 cats of European race with shorthair, of which 9 were female and 6 were male, with ages of between 7 and123 months. All of the animals had symptoms of the eosinophiliccondition, such as pruritis, alopecia and erythema, and the skinmanifestations associated therewith and, more precisely, 6 subjects hadEP, 5 had EG and 4 had milary dermatitis (scabs). A numerical evaluationrelating to the intensity and location of the signs and symptoms wasassigned to each individual animal in accordance with the P.A.S.I.(psoriasis area severity index) “score” (Marks R. et al., 1989, Arch.Dermatol., 125:235-240). The improvements in the clinical signs and inthe associated lesions were evaluated on the 15th and 30th days oftreatment. The treatment consisted of a preparation in accordance withExample 3 of the pharmaceutical preparations given below, containing 120mg of micronized N-palmitoylethanolamide. The active ingredient wasadministered in a proportion of 10 mg/kg/die for 30 days.

Table 1 below summarizes the results of the test(PEA=N-palmitoylethanolamide):

SIGNS SYMPTOMS plaque-granuloma-miliary pruritis-erythema-alopecia scabs% % im- un- im- un- proved changed worsened proved changed worsened nottreated T15 0 80 20 0 85 15 T30 0 70 30 0 80 20 treated with compo-sition of Example 3 T15 14.3 85.7 0 30 70 0 T30 67 33 0 66.7 33.3 0treated with non- micro- nized PEA (10 mg/kg/die) T15 8.2 91.8 0 14.685.4 0 T30 52 48 0 51.4 48.6 0 treated with cortisones T15 28 72 0 40 600 T30 65 35 0 64.8 35.2 0

Example B Effect of Oral Treatment with N-palmitoylethanolamide in theTreatment of Tendonous Keloids in Competition Horses

Case 1

On initial examination, an 8 year-old thoroughbred male chestnutracehorse had a large keloid, soft to the touch, in the palmar region ofthe metacarpal of the lower left-hand limb in a proximal position on theprofound flexor tendon. The horse had undergone an operation on theabove-mentioned tendon 6 months previously for serious traumatic lesionof the sheath. The animal had a pronounced limp and was practicallyimmobilized.

Treatment for 30 days with the preparation of Example 1 of thepharmaceutical compositions given below, involving administration of 2g/die of micronized N-palmitoylethanolamide, brought about a regressionof the keloid by between 90 and 95%.

The animal was able to recommence competitive activity.

Case 2

Upon examination, a 3-year-old half-breed female bay racehorse had aspheroidal formation the size of a lemon, of soft connective tissue inthe latero-palmar region of the metacarpal of the left-hand front limb.The keloidal formation was connected to the profound flexor tendon. Thetendon had been burnt about four months previously. After treatment for30 days with the preparation of Example 1 of the pharmaceuticalpreparations given below, involving the administration of 2 g/die ofmicronized N-palmitoylethanolamide, the formation regressed completelyand the functionality of the tendon was completely restored.

Case 3

A 5-year-old male bay racehorse, had signs of recurrent, chronic tendoninflammation on the right-hand front profound flexor. 2 yearspreviously, the subject had undergone a tendonectomy for lesion to thesheath, from which it had never fully recovered. After treatment for 30days with the preparation of Example 1 of the pharmaceuticalpreparations given below, involving the administration of 2 g/die ofmicronized N-palmitoylethanolamide, the tendon was clearly reduced.After a further 30 days with the same treatment regime, the subject wascompletely cured with considerable benefit to its competitiveperformance.

Case 4

A 2 year-old thoroughbred male bay racehorse had acute tendinitis of theright-hand front profound flexor in the full inflammatory phase. As aresult of an operation performed for the reduction of tendonous oedema,the animal developed a considerable fibrotic reaction with theproduction of adhesions. 5 months after the operation, treatment wasstarted with the preparation of Example 1 of the pharmaceuticalPreparations given below, involving the administration of 2 g/die ofmicronized N-palmitoylethanolamide. After 30 days a considerableimprovement was noted and the treatment was continued for a further 60days.

After treatment for 90 days, the tendon was perfectly shaped and theadhesions previously found had completely regressed. The animal returnedto competitive activity.

It is clear from the results given above that N-palmitoylethanolamidecan advantageously be used in the treatment of eosinophilic granuloma incats, for both EP and EG lesions, and of tendonous keloids in horses,both when these conditions are acute and when they are chronic.

In the latter animal in particular, the treatment withN-palmitoylethanolamide seems to be the only effective cure fortendonous keloids which enables the horse to return to competitiveactivity.

The treatment of the cat with N-palmitoylethanolamide, on the otherhand, gave results comparable to treatment with cortisones, with thesubstantial advantage that it does not have the serious side effectstypical of these drugs.

The use of N-palmitoylethanolamide in micronized and/or co-micronizedform (for example, with lactose) is particularly advantageous inbringing about the positive outcome of the treatment.

Clearly, the use of N-palmitoylethanolamide, preferably in micronizedand/or co-micronized form, for the treatment of eosinophilic granulomain cats, for lesions in both EP and EG forms, and of tendonous kelids inhorses, may be extended to all animals, particularly felines andequines, which have conditions of the same type.

PREPARATION OF N-PALMITOYLETHANOLAMIDE (PEA)

PEA is a known compound and can be prepared in accordance with thesynthesis method described in EP 0 550 008 which is incorporated hereinby reference.

The micronization of PEA and its co-micronization with excipients wereperformed with compressed-air turbine micronizing apparatus. Thisapparatus is known and is not therefore described in greater detail.

The product obtained was subjected to analysis of the particles withMastersizer, μ version apparatus from Malvern Instruments Co. UK. Thefinal fineness of the PEA particles produced can be summarized asfollows:

particle size quantity % >14μ traces <10μ 96% approx.  <6μ 80%

It should be noted that this result of the micronization method obtainedwith PEA is surprising since it is unusual for a molecule of a lipidnature to produce particles with a mean fineness much less than 10μ. Theextreme fineness of the particles can be translated into improvedabsorption of the drug.

EXAMPLES OF PHARMACEUTICAL PREPARATIONS Example 1 Oral Powder for Horses

100 g contained: micronized N-palmitoylethanolamide 22.22 g maize starch77.78 g

Example 2 Oral Granules for Horses

100 g contained: N-palmitoylethanolamide co-micronized 35.0 g withlactose lactose co-micronized with N-palmitoyl- 28.0 g ethanolamidemaize starch 27.0 g carboxymethyl cellulose 10.0 g

Example 3 Tablets for Cats

Each tablet, divisible from 350 g, contained: micronizedN-palmitoylethanolamide 120 mg maize starch  30 mg lactose 115 mgcarboxymethyl cellulose  15 mg microcrystalline cellulose  60 mgmagnesium stearate  10 mg

Example 4 Oily Gel for Cats

100 g contained: N-palmitoylethanolamide co-micronized  2.5 g withlactose lactose co-micronized with  1.5 g N-palmitoylethanolamide soyalecithin 82.5 g geleol 12.0 g Vitamin E acetate  0.5 g

Example 5 Gel for Use on Oral Mucosae in Cats

100 g contained: micronized N-palmitoylethanolamide 300 mg hyaluronicacid, sodium salt 200 mg (titrated in bio-binding epitope) carbomer 280mg methyl paraoxybenzoate 200 mg ethyl paraoxybenzoate  50 mg fishflavouring 800 mg sorbitol  20 g demineralized water to make up to 100 g

In general, a composition for administration to cats contains from 20 mgto 4 g of PEA per 100 g of composition. A composition for administrationto horses contains from 15 g to 40 g of PEA per 100 g of composition.

Clearly, other pharmaceutical compositions containing apharmacologically effective dose of N-palmitoylethanolamide togetherwith pharmacologically acceptable excipients may be provided. Thesecompositions may be in the form of capsules, tablets, powders andpellets, and also in gastroresistant formulations for oraladministration and may also be produced with the use of preliminarymicroencapsulation, liposomization or micellization techniques. Fortopical routes, including the transdermal route, formulations insuppositories, micro-enemas, creams, ointments, sprays, gels, foams,dressings of various thicknesses and patches may be used. All possiblepharmaceutical forms indicated for the various administration routes mayalso be formulated with excipients or by technological processessuitable for producing fast-release or slow-release medicaments.

What is claimed is:
 1. A method for treating eosinophilic granuloma in aFeline, said method comprising administering a pharmaceuticalcomposition, wherein the composition is comprised ofN-palmitoylethanolamide.
 2. The method according to claim 1, wherein theFeline is a cat.
 3. The method according to claim 1, wherein theN-palmitoylethanolamide is present in micronized form or isco-micronized with an excipient.
 4. A pharmaceutical compositioncomprised of N-palmitoylethanolamide in micronized form or co-micronizedwith an excipient, together with pharmaceutically acceptable excipients.5. The pharmaceutical composition according to claim 4 comprising from20 mg to 4 g of N-palmitoylethanolamide per 100 g of composition.
 6. Thepharmaceutical composition according to claim 4 comprising from 15 g to40 g of N-palmitoylethanolamide per 100 g of composition.
 7. Thepharmaceutical composition according to claim 4 in a form chosen fromthe group consisting of oral powder, oral granules, tablets and gel. 8.A process for the preparation of a pharmaceutical composition comprisingthe step of micronizing or co-micronizing N-palmitoylethanolamide withan excipient.